Methods of fabricating a heart valve delivery catheter

ABSTRACT

Inflatable devices are disclosed including a surface which has a network of polymer chains and is configured to be inflatable into a therapeutically or diagnostically useful shape, and at least one ultrashort laser pulse-formed modification in the surface. The network can, for example, include a network morphology that is substantially unchanged by modification with the ultrashort pulse laser. Ultrashort laser pulses can be laser pulses equal to or less than 1000 picoseconds in duration. Advantageously, the etching process uses a relatively low-heat laser to avoid significant heating of surrounding polymers while modifying the surface (and other structures) of the device. The process is configured so that the polymer chain morphology adjacent the modification is substantially unaffected by the low-heat laser. The resulting inflatable device has customized surface features while still retaining substantially homogenous polymer network morphology. This preserves the elasticity, especially the surface elasticity, of the inflatable device.

RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.16/940,833, filed Jul. 28, 2020 and now issued as U.S. Pat. No.11,305,098, which is a continuation of U.S. application Ser. No.15/815,599, filed Nov. 16, 2017 and now issued as U.S. Pat. No.10,722,693, which is a divisional of U.S. application Ser. No.14/938,761, filed Nov. 11, 2015 and now abandoned, which claims thebenefit of priority to U.S. Provisional Application No. 62/082,241,filed Nov. 20, 2014, which is incorporated by reference in its entiretyfor all purposes.

FIELD OF THE INVENTION

This invention relates to the field of inflatable medical devices fordiagnostic and therapeutic applications, particularly those designed toexpand within an anatomical space.

BACKGROUND OF THE INVENTION

Inflatable devices are used in many surgical and minimally invasivesurgical (MIS) techniques and settings. Medical balloons with thinnerwalls, higher strength, and smaller profiles are designed to withstandhigh inflation pressures and are well suited for use in a broad range ofdiagnostic and therapeutic procedures. They can be produced in a varietyof lengths, diameters, and shapes, including complex custom shapes forspecific applications, and supplied with specialty coatings for addedperformance. In a typical MIS procedure, uninflated devices arepositioned within an anatomical space and then filled with air or fluidto expand the device and possibly the anatomical space itself. Thisprocedure is used to deliver a prosthetic heart valve or stent to acardiac or vascular structure. Alternatively, an inflatable device canbe used to dilate an anatomical structure, as in angioplasty procedures.Other surgical procedures that incorporate the use of inflatable devicesinclude, for example, kyphoplasty, nephrostomy, gastric balloonplacement, endometrial ablation, laparoscopic hernia repair and renaldenervation. Furthermore, inflatable devices can be used in theobstruction, dilation and/or stent placement within the followinganatomical structures: sinuses, intestines, lacrimal ducts, Carpaltunnels, Eustachian tubes, the uterus, ureters, bile ducts, the trachea,the esophagus, the urethra, and the nasal passages. This list does notinclude all procedures that use inflatable devices, but is meant todemonstrate the breadth of this invention's relevance.

By way of example, inflatable devices are used in transcatheter aorticheart valve delivery procedures. In this procedure, a guidewire isdelivered through the femoral artery, through the patient's vasculatureto the native aortic valve, and placed within the left ventricle. Afirst balloon mounted on a catheter is inserted over the guidewire intothe aortic valve and inflated to widen the structure. The first balloonis removed back down the guidewire. A second, folded balloon carryingthe new prosthetic heart valve is delivered to the patient's diseasedaortic valve. Alternatively, a prosthetic heart valve may be moved ontothe balloon once it is inside the patient's body. Once positioned, thefolded balloon is inflated and the previously crimped valve is expandedto its full diameter. At its full diameter, the stent is lodged withinthe native heart valve. The second balloon is deflated and is routedback down the patient's vasculature and out the femoral artery via theguidewire, leaving the new valve in place.

Given their role in treating a range of patient conditions, improvementsin inflatable devices are highly desirable.

SUMMARY OF THE INVENTION

The inventors have advantageously modified the surface (and otherstructures) of inflatable devices, such as balloons, using low heatlasers, such as ultrashort pulse lasers, while avoiding significantheating of the polymer surrounding the modification. The inventors haveconfigured the process so that the polymer chain network morphologysurrounding the modification is substantially unaffected by thermaleffects. The resulting inflatable device has customized surface featureswhile still retaining a substantially unchanged polymer networkmorphology surrounding the low heat laser-formed modification. Thispreserves the elasticity and other mechanical properties of theinflatable device.

In one implementation, ultrashort laser pulses can be laser pulses equalto or less than 1000 picoseconds in duration. In another implementation,ultrashort laser pulses can be equal to or less than 1000 femtosecondsin duration.

In one implementation, the inflatable devices have a wall which has asurface. The wall is configured to be inflatable into a therapeuticallyuseful shape. The wall also has at least one low heat (or ultrashort)laser-formed modification on the surface. The wall is at least partiallyformed of a polymer, and therefore has a network of polymer chains. Thenetwork of polymer chains can have a network morphology. The networkmorphology surrounding the low heat laser-formed modification issubstantially unaffected by thermal effects.

The therapeutically useful shape can include a body, leg and coneregions. These regions are arranged along a longitudinal axis thatextends through them.

The laser formed modification can be on the inner surface of the wall ofthe device. For example, the low heat laser formed modification can beon an inner surface of the leg region.

In other implementations, the device can have multiple layers, such asan inner layer and an outer layer. The low heat laser-formedmodification can include a recession formed on the outer layer. Theouter layer can be radiopaque to facilitate locating it during surgicalprocedures.

The low heat laser-formed modification, for example, can be one or morerecessions in the surface. The recessions can, for example, increasefriction on the surface of the inflatable device. The recessions canhave different configurations. For example, the recessions can extendparallel to the longitudinal axis of the device. The recessions can bein a spaced, parallel arrangement and extend circumferentially aroundthe body region.

The device can include a circumferential perimeter. The recession in thesurface extends around at least a portion of the circumferentialperimeter. The recession can even extend entirely or fully around thecircumferential perimeter. The inflatable device can include a pluralityof the circumferentially extending recessions. They can be spaced apartfrom each other and in a parallel arrangement, forming a stripe-likepattern.

In another implementation, the recession can be etched into the coneregion of the device. For example, the recession can extend fromadjacent the leg region to the body region. And the recession cancontinue over an axial length of the body region. In an implementationwith two cone regions, the recession can extend over both cone regionsas well as the body region.

The inflatable device can include a plurality of recessions. Therecessions can be on the cone region and extend only partially betweenthe leg and body regions. The recessions themselves can change in width,such as by tapering as they extend toward the leg region.

The plurality of recessions can have geometric shapes, such as circles.For example, the circles can be etched in pattern on the body region ofthe device.

Methods include fabricating an inflatable device by applying low heatlaser pulses to a surface of the inflatable device. And the low heatlaser pulses can be applied to leave a network morphology surroundingthe modification substantially unaffected by thermal effects.

The method can also include forming a body, leg and cone regions about alongitudinal axis extends through the regions. The low heat laser pulsescan be applied to increase or reduce a friction of the surface.

The low heat laser pulses could be applied to an inner or outer surfaceof the inflatable device. For example, the inner surface could bepartially ablated to remove material.

In a multi-layered wall, the low heat laser pulses can be used to revealan inner layer beneath an outer layer. In this manner, excess materialof the outer layer serving no functional benefit can be removed.

The different regions can also be ablated, such as the cone, body andleg regions, selectively, for desired performance parameters. Forexample, the method can include ablating circumferentially around thebody of the inflatable device to form strips or stripes.

The application of low heat laser pulses can include applying ultrashortlaser pulses equal to or less than 1000 picoseconds in duration. Inanother implementation, ultrashort laser pulses can be equal to or lessthan 1000 femtoseconds in duration.

Ultrashort laser pulse-formed modifications can enable tighter folding,more predictable burst pressure, better bonding to external devices suchas catheters, the ability to coordinate inflation of various parts ofthe device, addition of friction or physical features that preventsliding of above-lying surfaces (such as valves or stents), removal ofadditional surface layers from selected areas of the device, and/oraddition of markings that would assist during folding or during surgicalprocedures.

These and other features and advantages of the implementations of thepresent disclosure will become more readily apparent to those skilled inthe art upon consideration of the following detailed description andaccompanying drawings, which describe both the preferred and alternativeimplementations of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1C are schematics of inflatable devices prior to the low heatlaser pulse-formed modifications;

FIG. 1D is an enlarged view of the multiple layers of the inflatabledevice of FIG. 1C, prior to the low heat laser pulse-formedmodifications;

FIG. 2A is a schematic of an inflatable device after modification withlow heat laser pulses;

FIG. 2B is an enlarged view of a region of interest from FIG. 2A;

FIG. 3 is a schematic of another inflatable device after modificationwith low heat laser pulses;

FIG. 4A depicts the cone region of an inflatable device prior tomodification with low heat laser pulses;

FIG. 4B depicts an inflatable device with low heat laser pulse formedmodifications in the cone region;

FIG. 5A depicts the leg region of an inflatable device prior tomodification with low heat laser pulses;

FIGS. 5B-D show inflatable devices with low heat laser pulse formedmodifications to the leg region;

FIG. 6 is a schematic of an inflatable device with low heat laser pulseformed modifications to the cone regions;

FIGS. 7A-C are schematics of inflatable devices with low heat laserpulse formed modifications to the body regions;

FIGS. 8A-C are schematics of inflatable devices with low heat laserpulse formed modifications along the longitudinal axis;

FIG. 9 is a schematic of an inflatable device;

FIG. 10 is a schematic of an inflatable device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Disclosed herein are embodiments of inflatable devices with specialsurface features created or facilitated by low heat, or ultrashort,laser pulse formed modifications. Implementations of the presentdisclosure now will be described more fully. Indeed, theseimplementations can be embodied in many different forms and should notbe construed as limited to the implementations set forth herein; rather,these implementations are provided so that this disclosure will satisfyapplicable legal requirements. The following description of certainexamples of an inflatable device should not be used to limit the scope.Other examples, features, aspects, embodiments, and advantages of theinflatable medical device will become apparent to those skilled in theart from the following description. As will be realized, the inflatabledevice is capable of additional aspects, all without departing from thespirit of the inflatable device. Accordingly, the drawings anddescriptions should be regarded as illustrative in nature and notrestrictive.

For purposes of this description, certain aspects, advantages, and novelfeatures of the embodiments of this disclosure are described herein. Thedescribed methods, systems, and apparatus should not be construed aslimiting in any way. Instead, the present disclosure is directed towardall novel and nonobvious features and aspects of the various disclosedembodiments, alone and in various combinations and sub-combinations withone another. The disclosed methods, systems, and apparatus are notlimited to any specific aspect, feature, or combination thereof, nor dothe disclosed methods, systems, and apparatus require that any one ormore specific advantages be present or problems be solved.

Features, integers, characteristics, compounds, chemical moieties, orgroups described in conjunction with a particular aspect, embodiment orexample of the invention are to be understood to be applicable to anyother aspect, embodiment or example described herein unless incompatibletherewith. All of the features disclosed in this specification(including any accompanying claims, abstract, and drawings), and/or allof the steps of any method or process so disclosed, can be combined inany combination, except combinations where at least some of suchfeatures and/or steps are mutually exclusive. The invention is notrestricted to the details of any foregoing embodiments. The inventionextends to any novel one, or any novel combination, of the featuresdisclosed in this specification (including any accompanying claims,abstract, and drawings), or to any novel one, or any novel combination,of the steps of any method or process so disclosed

It should be appreciated that any patent, publication, or otherdisclosure material, in whole or in part, that is said to beincorporated by reference herein is incorporated herein only to theextent that the incorporated material does not conflict with existingdefinitions, statements, or other disclosure material set forth in thisdisclosure. As such, and to the extent necessary, the disclosure asexplicitly set forth herein supersedes any conflicting materialincorporated herein by reference. Any material, or portion thereof, thatis said to be incorporated by reference herein, but which conflicts withexisting definitions, statements, or other disclosure material set forthherein will only be incorporated to the extent that no conflict arisesbetween that incorporated material and the existing disclosure material.

As used in the specification, and in the appended claims, the singularforms “a,” “an,” “the,” include plural referents unless the contextclearly dictates otherwise. The term “comprising” and variations thereofas used herein is used synonymously with the term “including” andvariations thereof and are open, non-limiting terms.

As used herein, inflatable devices include medical balloons. Forexample, inflatable devices include medical balloons such as those usedin therapeutic or diagnostic procedures.

As used herein, ablating or etching is a process by which material isremoved using a laser. Modifications to an inflatable device, forexample, low heat-laser pulse formed modifications, can be formed byablating or etching.

The inventors have noted several shortcomings in inflatable devices ofthe prior art. They have endeavored to address these shortcomings byimplementing the principles of this invention. Inflatable device surfacemodifications are desirable for many reasons, which will be explained ingreater detail below. However, modification with laser pulses canoverheat the polymer, disorienting the network of polymer chains thatsurround the modification. This disorientation decreases the overallstrength of the device.

The inventors have designed a process wherein modifications by arelatively low heat laser (e.g., ultrashort pulse laser) do not heat thesurrounding polymer. Additional details of such low heat lasers orultrashort pulse lasers are disclosed in U.S. Patent ApplicationPublication No. 2013/0110097 filed Sep. 17, 2012, which is incorporatedherein by reference. The polymer chain network morphology in the areasurrounding the laser pulse-formed modification is substantiallyunaffected by thermal effects, preserving the strength of the device.Low heat or ultrashort laser pulses as used herein are defined as laserpulses less than 1000 picoseconds in duration. In some implementations,low heat or ultrashort laser pulses can be less than 1000 femtosecondsin duration.

The inventors have realized or determined several design considerationsduring their development of the implementations of the invention.Procedures using inflatable devices benefit from transfer through narrowanatomical spaces in an uninflated state. To achieve this, theinflatable devices can benefit from being tightly folded underneath anexternal device such as a valve or stent. The device in its folded stateshould generally have a narrow profile. This enables it to enter smalleranatomical spaces, reducing tissue damage. It also enables easierdelivery with lower friction.

However, certain fabrication processes create unnecessary bulk. Forexample, one method of producing an inflatable device is to blow mold apolymer tube into a balloon shape. This forms thinner areas that willultimately inflate to wider dimensions, creating the body of the device.The areas outside the mold are not meant to inflate. These become thelegs of the device. The transition from the thinner body area to thethicker leg region is the cone of the device. In this region, the wallchanges from thin to thick. If the walls of these regions could bethinned, the overall profile of the folded inflatable device would bethinner and could fit into narrower anatomical spaces. Low heat laserpulse formed modifications can be used to even the wall thicknesspost-molding, improving the consistency of the bonding strength of theinflatable devices to external devices such as catheters. Furthermore,the low heat lasers could be used to newly create features that enhancebonding to external devices.

Precisely targeted placement and orientation of a valve or stent alongan inflatable device is a factor in the success of the procedure and tothe safety of the patient. Proper timing of inflation is important toreduce flaring of the ends of the valve or stent. Similarly, a valve orstent increases the resistance to inflation, and areas of the inflatabledevice around the external device can inflate first. This creates anundesirable dog-bone shape. Improvements to valve stabilization andinflation timing would be highly beneficial, as would the improvementsin the visualization of the inflatable device during delivery forassisting in orientation of the valve/stent.

The inventors have further observed that inflatable devices couldbenefit from heightened predictability of bursting pressure. The abilityto create inflatable devices with consistent wall thicknesses wouldenhance the prediction of burst pressure. Furthermore, the ability tothin a specific region of an inflatable device would enable predictionof the precise bursting location, and to locate it to the region thatwould cause the least tissue damage, should it ever occur. Precisemanufacturing can even allow for the design of inflatable devices thatleak slowly and gently instead of bursting.

The inventors have addressed these issues by removing material fromprecise locations of the inflatable device using a low heat laser.Methods of laser-ablating excess material after molding have beendisclosed in the prior art, such as in U.S. Pat. No. 6,719,774. However,the utility of such methods is limited because heat produced by thelaser causes disorientation of the nearby polymer network, whichincreases chances of bursting at lower inflation pressures. In contrast,alignment of the network of polymer chains is associated with increasedresistance to bursting. Thus, the maintenance of an oriented morphologyis desirable for inflatable devices.

The inventors have determined that ultrashort laser pulses have anon-thermal laser-material coupling that protects against deleteriouseffects to the polymer network adjacent to the laser modification. Theterm “low heat laser” as defined herein includes lasers that can beoperated to ablate the polymeric wall compositions at temperatures lessthan a temperature at which the adjacent polymeric wall compositionand/or organization starts to degrade. Generally, most bio-absorbableand many bio-compatible polymers have a melting point of below 100degrees Celsius. The low heat lasers can be, for example, near-IR lasersystems that have a maximum pulse energy of 40 micro-joules with a pulseduration of less than 400 femtoseconds at 200 KHz. Another examplesystem has a maximum pulse energy of 200 micro-joules with a pulseduration of 10 picoseconds. Still another example system is afiber-based ultrafast laser that is mode-locked and can generateultrashort pulses centered at about 1552.2 nanometers. The power of thissystem can be 5, 10 or 20 watts. The pulses produced can be less than800 femtoseconds.

FIGS. 1A-D show examples of inflatable devices prior to modification bylow heat lasers. These exemplary devices are manufactured by molding apolymer tube into a balloon shape. This fabrication process createscertain characteristics that are improved by the modifications disclosedherein. Inflatable devices can be fabricated to suit various anatomicalstructures without detracting from the function of the device.

An inflatable device 101 that has not yet been modified by ultrashortlaser pulses is shown in FIGS. 1A-D. As used herein, the terms “modify,”“modified,” and “modifications” refer to actions of the ultrashort laserpulses on the inflatable device surface. The term “unmodified” refers toprefabricated inflatable devices which have not been modified byultrashort laser pulses. The inflatable device 101 of FIG. 1A comprisesa body region 108, a pair of leg regions 104, and a pair of cone regions106. These regions define a longitudinal axis 103 extending generallyalong a direction of a guide wire (not shown) supporting the device.Each of the cone regions 106 has an end 109 adjacent the leg region 104.The inflatable device further comprises a wall 121 having an outersurface 105 and an inner surface 107. The regions 104, 106 and 108 aresub-portions of the wall 121.

Implementations of the inflatable devices 101 disclosed herein can beused alone or in conjunction with other devices, including but notlimited to prosthetic heart valves and stents. In this manner, aprosthetic valve 102 or other device can be delivered along with theinflatable device 101 (both in a compressed configuration) to arelatively inaccessible location in the body, such as percutaneously toa non-functional native heart valve. Then the device 101 is inflated toexpand the valve 102 into an expanded condition. For example, in FIG.1A, the expanded valve 102 is situated around the expanded body region108 of the inflatable device 101.

Referring again to FIG. 1A, the body region 108 is positioned adjacentto and extends between the cone regions 106. The body region 108 has anelongate shape (as shown by the longitudinal cross-section shown in FIG.1A) that extends in the direction of the longitudinal axis 103. The bodyregion 108 of the inflatable device 101 also has a transverse crosssection (not shown) extending perpendicular to the longitudinal axis103. The transverse cross section can have an extruded, symmetricalshape, such as a circular or square shape, or some other geometric orirregular shape depending upon the desired application

Generally, the length and diameter of the body region 108 and the restof the device can be adapted to suit various anatomical structures or toperform various functions. For example, FIG. 1B shows a variation on thedimensions of the body region 108. The length of body region 108 of theimplementation of FIG. 1B, for example, is shorter than that of theimplementation shown in FIG. 1A. The diameter of the body region 108, onthe other hand, is larger in FIG. 1B than in FIG. 1A. The dimensions ofthe inflatable devices can also vary when they are in their crimped,folded states.

Prior to modification with ultrashort laser pulses, the body region 108of the inflatable device 101 shown in FIG. 1A can have slight variationsin wall thickness 118. These slight variations are caused by thefabrication process. In some examples, the thickness of the wall maychange gradually along the length of the body region 108.

Referring again to FIGS. 1A-D, the unmodified inflatable device 101 alsoincludes the cone regions 106. Each of the cone regions 106 extends froma wide end adjacent the body region 108 to a narrow end 109 adjacent theleg region 104. The cone regions 106 have a frustoconical shape arrangedcircumferentially around the longitudinal axis 103. A diameter of thecone region 106 extends perpendicular to the longitudinal axis 103.

As described above for the body region, the dimensions of the coneregions 106 vary depending upon the application. The cone regions 106 ofthe inflatable device 101 shown in FIG. 1A have a cone region wallthickness 116 that tapers moving away from the narrow end 109. Thisvariation occurs during the blow molding process, as the central regionof the polymeric tube (which becomes the body region 108) is stretchedto a greater extent than the edges of the tube. For example, the coneregion wall thickness 116 of the unmodified inflatable device 101 can bethicker at the narrow end 109, adjacent to the leg region, than at end108, adjacent to the body region. Similar to the body region, thefabrication process can also cause slight, localized variability in thecone region wall thickness 116.

As shown in FIG. 1A, the inflatable device 101 includes the pair of legregions 104 at opposite ends of the inflatable device. In thisimplementation, the leg regions are non-inflatable ends of the wallmaterial 121 used to construct the inflatable device. The leg regionscan be compressed onto a guide wire for delivery into an anatomicalspace. The inflatable device is mounted onto a guide wire or catheter(not shown) via axial openings 112.

While the implementations discussed herein include a pair of legregions, it is possible to fabricate inflatable devices with a singleleg and cone region. Other implementations can have a range of shapesformed by the wall 121, such as square, bulbous or irregular shapes thatdo not necessarily include the particular regions 104, 106 and 108 ofthe illustrated implementations. These alternate implementations stillbenefit from the formation of modifications thereon.

The leg regions 104 extend from a cone region end 109 away from the bodyregion 108 to a free end 110. The leg regions 104 have a length in thedirection of the longitudinal axis 103 and a transverse cross sectionextending perpendicular to the longitudinal axis 103. The diameter andwall thickness, generally, can be a reflection of the original polymerictube used to form the inflatable device 101. The fabrication process cancause slight variability in the leg region wall thickness 114 along itslength.

The inflatable device 101 shown in FIG. 1A has a wall 121 with an outersurface 105 and an inner surface 107. The outer surface 105 is fartherfrom the longitudinal axis 103 than the inner surface 107. The outersurface generally contacts above-lying surfaces of an external devicemounted thereon, including for example the inner surfaces of aprosthetic heart valve 102 or stent.

Part of the function of the body region 108 of the inflatable device 101is to allow axial positioning of the device or structure which it isexpanding. To this end, the interface between the surface and theexternal device generates an improved frictional retaining force via themodifications of the surface. Another way to understand the effect offriction is to quantify the surface roughness of the inflatable device101.

Generally, the inflatable device's surfaces 105, 107, and walls 121 areformed of a polymer material, at least in part. The polymer materialinherently includes a network of polymer chains having a networkmorphology. It is understood that the walls' 121 elasticity and othermechanical properties are affected by the network morphology of thepolymer chains making up the surfaces 105, 107, walls 121, or portionsthereof. Without being wed to theory, it is also understood that thenetwork morphology is affected by the polymer chain orientation.

Although a range of materials (and combinations of materials) arecapable of being inflated at the pressures needed to perform functions,polymeric materials for layers or compounds are particularly well suitedfor applications. They have the flexibility to shrink to small diametersand the elasticity to expand without bursting. Polymeric materialsinclude, for example, thermoplastic and thermoset polymers. Suchpolymers include, for example, PET, Nylon, Pebax, polyurethane,polyetherurathane, PVP, PEO, HDPE, and LDPE.

To fabricate an inflatable device 101, a polymer can be blow molded intoa hollow balloon shape. The central region of the hollow polymer has athinner body region 108 that will ultimately inflate to widerdimensions. The cone region 106 and its tapered wall 116 are products ofthis molding process. The leg regions 104 are not molded and thereforedo not substantially inflate. The leg regions 104 can be bound to acatheter tube by mounting the device around openings 112 and bonding theleg material to the catheter tube. This bond can have a bonding strengththat varies with size and application. The bonding strength can bemeasured by a tensile test. In these examples, the low heat lasermodifications take place after the molding process. However, low heatlaser modifications can also take place prior to the molding processwithout deviating from the inventive concept.

As seen in FIG. 1C, in another implementation, inflatable device 101 hasmultiple wall layers 120, 121 prior to modification by ultrashort laserpulses. The outer layer 120 is the farthest layer from the longitudinalaxis 103, and the inner layer 121 is closest to the longitudinal axis103. An enlarged version of the multiple surface layer inflatable device101 is shown in FIG. 1D.

Additional surface layers can have several functions. For example, anadditional surface layer can be designed to increase friction, reducefriction, or add radiopacity to the device. And, as described below, thepresence of multiple layers allows them to be selectively etched awayand/or revealed to generate unique, customized properties for theinflatable devices 101.

The surface roughness of the inflatable device 101 can impact function.The outer layer 120 can be included to alter the surface roughness—suchas by using a material that is inherently rougher than the inner layer121. And, in areas where reduced roughness is desired (such as on thecone regions 106 for easier insertion into body lumens) the outer layer120 can be etched away.

Multi-layer implementations similarly are not limited to the two layersshown in FIG. 1C. Instead, three, four or more layers can be used tocustomize the properties of the inflatable device 101 to differentapplications and for different etching effects. The layers can befabricated from materials such as Nylon, Pebax, PET, polyurethane,polyetherurathane, PVP, PEO, HDPE, LDPE. Radiopacity can be incorporatedin an outer layer by mixing the polymer solution with a pacifier, suchas Tungsten powder, prior to fabrication. Platinum, gold, palladium,iridium, magnesium, zinc, tungsten, tantalum, iron, iodine salts,bismuth salts, or barium salts can also be incorporated into an outerlayer to yield a radiopaque inflatable device.

FIG. 2A shows the inflatable device 201 of FIG. 1A with recessionsformed by ultrashort laser pulses or some other low heat laser. Inparticular, in this implementation, the outer surface 105 of the bodyregion 208 has been partially ablated by ultrashort laser pulses. Theablations create one or more recessions 211 in the outer surface. Therecession 211 has a length that extends parallel to the longitudinalaxis 203. The recession 211 also extends around a perimeter of the body208 of the inflatable device 201—largely forming a tubular-shape ofnegative space in the wall 221. The length of the recession 211 in theaxial direction can adapted to specific functions or applications. Forexample, the length can be mostly coextensive with the stent or valve202. In this manner additional clearance is provided for crimping thevalve 202 down to a smaller diameter for easier delivery.

FIG. 2B shows an enlarged portion of FIG. 2A with the ultrashort laserpulse-formed recession 211 in the body region 208. The wall 221 of thebody region has an original thickness 218 and an ablated wall thickness219. The original thickness 218 corresponds to thickness 118 of theunmodified inflatable device 101 shown in FIG. 1A. The ablated wallthickness 219 can vary by particular desired application, but in thecase of an inflatable device for expansion of a stent mounted heartvalve it can be about 1-40% of the original wall thickness 218.

The recession 211 shown in FIGS. 2A-B inflates to a larger diameter thanunmodified areas of the body region 108 because it has lower resistanceto the air pressure inside the inflatable device. This reduces dog-boneeffects at the ends and decreases the likelihood of damage tosurrounding tissue. At the same time, the ultrashort laser pulse-formedrecession leaves the adjacent surface polymer network morphologysubstantially unaffected by thermal effects.

FIG. 3 shows another inflatable device 301 with recessions 311 formed byultrashort laser pulses. In this implementation, the outer portion ofthe surface of the body region 308 has been ablated by ultrashort laserpulses so as to create two recessions 311 in the surface of the bodyregion. The recessions 311 have lengths that extend parallel to thelongitudinal axis 303. The recessions 311 extend fully around theperimeter forming two cylindrical strips on opposite sides of the valve302. The wall of the body region has an original thickness 318 and anablated wall thickness 319. The original thickness 318 corresponds tothickness 118 of the unmodified inflatable device 101 shown in FIG. 1A.

Certain areas of the body region of an unmodified inflatable device(such as the one shown in FIG. 1A) can inflate before others, which canresult in slight axial movements of the valve or stent. The ultrashortlaser pulse-formed recessions 311 of FIG. 3 have lower resistance to theair pressure inside the inflatable device. They inflate to a widerdiameter than the unmodified areas of the body region. They also inflateprior to the region that is under the valve or stent 302. These aspectsreduce axial movements of the valve or stent 302 during inflation.

FIG. 4A shows an enlarged view of the cone 106 and leg regions 104 ofthe inflatable device 101 shown in FIG. 1A. FIG. 4B shows the inflatabledevice 401 after ultrashort laser pulse formed modifications to theouter surface 405 of the cone region 406. In this implementation, excessmaterial is ablated fully cylindrically around the perimeter of theouter surface 405 of the cone region 406. Advantageously, the reducedcone thickness 416 facilitates tighter folding of the inflatable device.This enables the device to be used in narrower anatomical spaces.

FIG. 5A shows an enlarged view of the unmodified inflatable device shownin FIG. 1A. Notably, the inner surface 107 of the leg region 104 has atapered shape defining the axial opening 112.

FIGS. 5B-D show inflatable devices 501 after ultrashort laser pulseformed modifications to the leg region 104. In particular, FIG. 5B showsthe original outer surface 105 of the leg region 104 ablated, creatingthe diminished leg region wall thickness 514. The ablation of the excessmaterial extends circumferentially around the perimeter of the legregion 504. The reduction in leg thickness enables tighter folding ofthe inflatable device.

As described above and as demonstrated in FIG. 5A, the necking processcan lead to unevenness in the wall 121 along the length of the legregion. In the implementation shown in FIG. 5C, low-heat laser pulseshave been directed through the outer surface of the leg region to ablatethe original inner surface 107 of the leg region 104. This creates athinned inner surface 507 and diminished leg region wall thickness 514.This allows for a larger wire or other mating part to fit within theopening 507 for better bonding. In addition to enabling tighter folding,the ablation creates a smoother inner surface 507 to raise bondingstrength to external devices such as catheters and guidewires. Inaddition, less and/or more consistent thickness leg material willgenerate a more consistent heating profile (and better bonding) during,for example, a heat-fusion bonding process. Laser etching of the legmaterial can occur before or after bonding. After etching the innersurfaces of an inflatable device, the device can undergo a cleaningprocess, such as ultrasonic cleaning, to remove debris prior to use in apatient.

FIG. 5D shows another inflatable device 501 with a bonding feature 511in the leg region 504. The bonding feature 511 is created by ablation ofpart of the inner surface 507 by ultrashort laser pulses. The bondingfeature 511 extends from the end 510 of the leg region along thelongitudinal axis 503. The shape of the bonding feature 511 can befrustoconical, wedge, tapered or hook shaped, for example, or can besome increase in surface roughness. The bonding feature 511 reduceslongitudinal slippage of an external device, such as a catheter orguidewire, that has been bonded to inner surface 507 of the inflatabledevice. For example, the wedge shape of bonding feature 511 in FIG. 5Dcan mate with a flare at an end of a catheter or guidewire, raising theforce necessary to decouple the catheter or guidewire from theinflatable device.

FIG. 6 shows an inflatable device 601 with ultrashort laser pulse-formedrecessions 622 in the inflatable device 101 of FIG. 1A. In thisimplementation, the recessions 622 are formed on the cone region 606.The recessions 622 can extend from adjacent the end 609 of the coneregion 606 in the direction of the body region 608. The width ofrecessions 622 can taper gradually from larger proximate the body region608 toward the end of the cone region 609. Recessions 622 promotefolding in specified locations, leading to better organization of thefolds and thus tighter folding.

FIGS. 7A-C show implementations for increasing the frictional forcebetween the inflatable device 701 and an above-lying surface. Recessions724 are ablated onto the body region 708 using ultrashort laser pulses.The increased frictional force induced by these recessions decreasesmovement of a valve or stent along the body region of the inflatabledevice, improving the consistency and safety of the procedure.

FIG. 7A shows an inflatable device 701 with circular ultrashort laserpulse-formed recessions 724 for increased frictional force. A pluralityof recessions 724 can be uniformly or randomly spaced around the outersurface 705 of the body region 708. While the recessions of thisimplementation are shown as circles, recessions 724 can be other shapessuch as squares, rectangles, or triangles. These recessions prevent bothaxial and circumferential slippage of the valve or stent. Differentpatterns of different types of recessions can be employed on differentparts of the inflatable device, such as circles of one diameter on thebody region and circles of another diameter on the cone regions.

The implementation shown in FIG. 7B has a plurality of ultrashort laserpulse-formed recessions 724 that extend circumferentially around theperimeter of the device. The recessions have a width in the directionparallel to the longitudinal axis 703 and a depth into the outer portion705 of the surface of the body region. The recessions 724 are spacedalong the longitudinal axis 703. The circumferential orientation of therecessions 724 helps to prevent slippage of the stent or other device inthe direction of the longitudinal axis 703.

The implementation shown in FIG. 7C has a plurality of ultrashort laserpulse-formed recessions 724 that extend across the body region 708 inthe direction of the longitudinal axis 703. The recessions are spacedaround the circumference of the body region 708. The longitudinalorientation of the recessions helps to prevent slippage of the stent orother device around the circumference of the body region 708.

FIGS. 8A-C show inflatable devices 801 designed to burst at specificlocations if inflated past predetermined pressures. In particular, theultrashort laser pulse-formed modifications are tailored to weaken thewall in a particular pattern. This results in a predictable burstpattern when the inflatable device is overinflated, which can make iteasier to retrieve a ruptured device. The recessions can also promoteslow, gentle leaking of air (or other fluids) in the event ofoverinflation, as opposed to bursting.

In the implementation of FIG. 8A, an ultrashort laser pulse-formedrecession 826 extends from adjacent end 809 of the cone region 806 inthe direction of the body region 808. In the implementation of FIG. 8B,the ultrashort laser pulse-formed recession 826 extends from adjacentthe end 809 of the cone region 806 and across the body region 808. Inthe implementation of FIG. 8C, the recession 826 extends from adjacentthe end 809 of the cone region 806, across the body region 808, andtoward the end of the second cone region 807.

In FIGS. 8A-C, the bursting pattern would occur in the longitudinaldirection. This facilitates retrieval of a ruptured inflatable device.Or the longitudinal etched recessions will result in a gentler leakageas opposed to bursting. Another advantage is that the axial recessions826 can promote axial blood perfusion, enabling blood or drug flowaround the inflatable device during and after inflation.

FIG. 9 shows an inflatable device 901 with modifications of amulti-layer inflatable device, such as the device 101 of FIG. 1C. Partsof the outer layer 920 have been removed by ultrashort laser pulses,exposing the inner layer 921. The remaining outer layer 920 extends as acircumferential, tubular shaped layer around the perimeter of theinflatable device 901. The length of outer layer 920, as measuredparallel to the longitudinal axis 903, can be formed to substantiallymatch the length of an external device, such as a stent mounted heartvalve 902. The outer layer 920 of FIG. 9 can have different propertiesthan the inner layer 921. For example, the outer layer 920 can changethe frictional properties between the inflatable device 901 and anabove-lying surface. Meanwhile, ablation of the excess outer surfacematerial allows for tighter folding of the inflatable device 901.

FIG. 10 shows an inflatable device 1001 with recessions 1028 formed byultrashort laser pulses to serve as identifying marks. Recessions 1028can be located on the body region 1008 as seen in FIG. 10. Therecessions 1028 can also (additionally or alternatively) be located onthe cone region or the leg region. In FIG. 10, recessions 1028 extendcircumferentially around the perimeter of the body region 1008. Theserecessions can serve as identifying marks to assist in the assembly ofthe inflatable device. Markings on the inflatable device leg can helpidentify cutting length or welding bands, for example. They can alsoassist in the alignment of the stent or valve during anatomicalimplantation. Markings can have indicia to identify parts, productmodels and inflatable device sizes as another example.

The implementation of FIG. 10 can also have multiple layers—such as aradiopaque outer layer 1020. The recessions 1028 in the outer layerselectively remove the radiopaque outer layer 1020, for example, toreveal its orientation on radiological instruments during medicalprocedures.

The ultrashort laser pulse formed modifications disclosed herein havethe advantage of having low or no thermal impact on the inflatabledevice wall. The absence of significant thermal impact preserves theproperties of the inflatable device. For example, use of the ultrashortlaser preserves the homogeneity of the polymer orientation of apolymeric wall.

Advantageously, the inflatable devices disclosed herein can be used toimprove various inflatable device based medical procedures, such as todeliver a prosthetic heart valve during a transcatheter valvereplacement procedure. As another example, the devices can be used todeliver a stent during percutaneous procedures. As another advantage,the laser etching procedure disclosed herein allows the thickness of thecone and body of a device to be changed independently—facilitatingvariations in expansion characteristics. Also, uniform wall thicknessfacilitates folding, retrieving and better general performance. Forexample, the legs of the inflatable device need to be thicker to allowstretching of the body without breaking the inflatable device. Laseretching allows the legs to be thinned for a lower profile, reducingfriction on the arterial walls during deployment and retrieval.

The various patterns of recession etching disclosed herein have a rangeof advantages. Reduction in body wall thickness results in resistance toformation of the dumb-bell (or dog bone) shape during expansion of astent or valve, resulting in a more accurate final outside diameter forthe device being delivered. This can be useful for aortic applications.Ablating one end selectively can result in a mushroom shape, which canbe helpful for bicuspid repair. Reduction of the cone region thicknessreduces inflatable device withdrawal forces. Ablating shallow rings inthe body at one or both ends facilitates earlier expansion of ringportions to limit axial movement of the stent or valve. Ablating shapedpatterns in the outer surface of the inflatable device wall increase thefriction force between the implantable and the inflatable device.Removal of wall material in an axial direction (or other location) cancreate a desired point, spot or pattern for failure of the inflatabledevice. Reduction of leg thickness reduces bond profiles and increasesefficiency of the bonding process. Also, shaping of the leg regions canincrease bond strength and precision.

Also, in multi-layered inflatable devices, the low-heat laser can beused to remove undesired layers from various locations. A dual layer canbe retained in the body region for increased puncture resistance andincreased (or decreased) friction between the inflatable device andstent, but removed from the cone and leg regions for profile andtackiness reduction. The inflatable device can also be modified tocreate “witness lines” or a mid-line to improve alignment of theinflatable device and stent or valve during crimping or other assemblysteps. Or the inflatable device can be etched with variousidentification marks.

Removal of wall materials from a center or body section reduces stent orvalve frame edge flaring, reducing impact on surrounding tissues duringdelivery. A tapered wall inflatable device could also be created tocreate a tapered outer or inner diameter in the vasculature, stent orvalve frame, to fit tapered anatomy, such as in the peripheralvasculature, for example.

Many modifications and other embodiments of the invention set forthherein will come to mind to one skilled in the art to which thisinvention pertains having the benefit of the teachings presented in theforegoing description. Therefore, it is to be understood that theinvention is not to be limited to the specific embodiments disclosed andthat modifications and other embodiments are intended to be includedwithin the scope of the appended claims.

What is claimed is:
 1. A method of fabricating a heart valve deliverycatheter, comprising: obtaining a polymer tube defined by a wall along alongitudinal axis having an inner surface and an outer surface, thepolymer comprising a network of polymer chains with a homogenous networkmorphology; blow molding the polymer tube into a hollow balloon shapehaving a central body region, a pair of leg regions on opposite ends ofthe balloon shape that are radially smaller than the central body regionand define axial openings therethrough, and a pair of cone regionsextending between the central body region and the leg regions; applyinglow heat laser pulses to an outer surface of the cone regions to ablatematerial and form a laser-formed modification in the outer surface ofthe cone regions, the low heat laser pulses being configured so as toleave the polymer network morphology surrounding the laser-formedmodification substantially unchanged; wherein the blow molded andlaser-modified polymer tube forms a balloon, bonding the leg regions ofthe balloon to a catheter; folding the balloon; and crimping a heartvalve around the central body region of the folded balloon.
 2. Themethod of claim 1, wherein the low heat laser pulses are applied tocreate a plurality of longitudinal recessions in the cone regions. 3.The method of claim 2, wherein the longitudinal recessions taper from anarrow width to a wider width toward the central body region.
 4. Themethod of claim 2, further including forming a second laser-formedmodification in the central body region to form recessions that enhancea frictional capacity of the central body region.
 5. The method of claim1, wherein the step of applying is done prior to the step of blowmolding.
 6. The method of claim 1, wherein the pulses are less than 1000picoseconds in duration and have a maximum pulse energy of 200micro-joules.
 7. The method of claim 1, wherein the laser-formedmodification extends parallel to the longitudinal axis in the coneregions.
 8. The method of claim 1, wherein the laser-formed modificationextends around a circumferential perimeter of the cone regions.
 9. Themethod of claim 1, wherein the laser-formed modification extendsparallel to the longitudinal axis and around a circumferential perimeterof the cone regions.
 10. The method of claim 1, wherein the low heatlaser pulses are applied to create a constant wall thickness in the coneregions.
 11. The method of claim 1, further including forming a secondlaser-formed modification comprising a wedge, a taper, or an increase insurface roughness on an inner surface of the leg region.
 12. The methodof claim 1, further including forming a second laser-formed modificationthat creates a diminished wall thickness of the leg region.
 13. Themethod of claim 1, further including forming a second laser-formedmodification in the central body region to form a recession that extendsparallel to the longitudinal axis and around a circumferential perimeterof the central body region to reduce the wall thickness in a portionthereof.
 14. The method of claim 1, further including forming a secondlaser-formed modification in the central body region to form recessionsthat enhance a frictional capacity of the central body region.
 15. Themethod of claim 14, wherein the recessions that enhance a frictionalcapacity of the central body region are formed in shapes selected fromthe group consisting of a plurality of discrete recessions uniformly orrandomly spaced around the outer surface of the central body region,recessions that extend circumferentially around the perimeter of theouter surface of the central body region and are spaced apart in thedirection of the longitudinal axis, and axial recessions that extendacross the central body region in the direction of the longitudinal axisand are spaced apart around the circumference of the central bodyregion.
 16. The method of claim 1, further including forming one or moresecond laser-formed modifications that alone or together serves as anidentifying mark to assist in the assembly of the inflatable device,help identify cutting length or welding bands, assist in the alignmentof the heart valve during anatomical implantation, or identifies parts,product models or inflatable device sizes.
 17. The method of claim 1,further including forming one or more second laser-formed modificationsthat are tailored to weaken the wall in a particular pattern and resultin either a predictable burst pattern or slow, gentle leaking ofinflation fluid when the balloon is overinflated.
 18. The method ofclaim 1, wherein the polymer tube has at least two polymer wall layersincluding an outer layer farthest from the longitudinal axis and aninner layer, the polymers in each respective outer or inner layercomprising a network of polymer chains with a homogenous networkmorphology
 19. The method of claim 18, wherein the outer layer isradiopaque.
 20. The method of claim 19, wherein the outer layer isremoved in a pattern that indicates an orientation of the balloon onradiological instruments.
 21. The method of claim 18, wherein thepolymer of the outer layer is inherently rougher than the polymer of theinner layer, and the low heat laser pulses are applied to the coneregions to facilitate passage of the balloon through body lumens. 22.The method of claim 18, wherein the low heat laser pulses are applied tothe central body region wherein the outer layer is removed to expose theinner layer, wherein a remaining portion of the outer layer extends as acircumferential, tubular shaped layer around the perimeter of theinflatable device, and a length of the remaining portion of the outerlayer substantially matches a length the heart valve.